All electronic circuits need a well regulated power supply to ensure proper operation of the circuit, which may be supplied by one or more voltage regulators. It may be possible to integrate a voltage regulator into an integrated circuit (IC) chip. It may also be possible to integrate a voltage regulator to other components of an integrated circuit. For example, in a hard disk drive (HDD), one or more voltage regulators may be integrated into a motor controller, which may provide one or more regulated supplies to the motor controller and/or other components or chips in the HDD (e.g., system-on-chip (SoC), preamplifiers, dynamic random access memory (DRAM) etc.).
FIG. 1 illustrates an exemplary on-chip voltage regulator 10, along with internal field effect transistor (FET) drivers, included in an integrated circuit chip 20. The voltage regulator 10 may be configured to supply regulated voltage to load 76 through an inductor 72 and/or a capacitor 74. In various embodiments, a dotted line 14 in FIG. 1 may indicate a boundary of the chip 20, and the load 76, inductor 72 and/or capacitor 74 may be external to the integrated circuit chip 20. It will be apparent to those skilled in the art that although the voltage regulator 10 is illustrated to supply regulated voltage to components external to the chip 20, in various embodiments, the voltage regulator 10 may also drive components internal to the chip 20 along with (or instead of) driving the external load 76.
In various embodiments, the voltage regulator 10 may include a driver 28, which may further include a high side driver 32 and a P-channel FET (PFET) driver 34. The high side driver 32 may be configured to drive the PFET driver 34, and hence, for illustrative purposes, the high side driver 32 and the PFET driver 34 have been illustrated as a single unit. It will be apparent to those skilled in the art that unlike the illustration of FIG. 1, the high side driver 32 and the PFET driver 34 need not be physically combined. In various embodiments, the driver 28 may also include a low side driver 36 configured to drive an N-channel FET (NFET) driver 38, also included in the driver 28.
In various embodiments, the voltage regulator 10 may also include a controller 24, which may be configured to control the operations of the driver 28, including the high side driver 32 and the low side driver 36. The controller 24 may receive a reference voltage Vref, and the voltage regulator 10 may be configured to regulate its output voltage to make it substantially equal to k*Vref, where Vref is the reference voltage and k may be a programmable constant.
In various embodiments, the integrated circuit chip 20 may also include a VDD pin 40, which may be configured to receive a supply voltage VDD (e.g., 5V); a ground pin GND 48, which may be coupled to a ground supply GND; a feedback pin FB 52, which may be configured to receive a feedback voltage Vout supplied to the load 76 (or a voltage proportional to the feedback voltage Vout, for example, M*Vout, where M is a programmable constant); and an output voltage pin OUT 44, which may be configured to output the regulated voltage. In various embodiments, the supply voltage VDD may be coupled to the high side driver 32 and/or PFET driver 34, the ground voltage GND may be coupled to the low side driver 36 and/or NFET driver 38, and the feedback signal FB may be coupled to the controller 24. The output of the high side driver 32 and/or PFET driver 34 and the output of the low side driver 36 and/or NFET driver 38 may be coupled to the output pin OUT 44.
In various embodiments, the high side driver 32 may control the switching of the PFET driver 34 such that the PFET driver 34 drives the output pin OUT 44 towards the supply voltage VDD 40. On the other hand, the low side driver 36 may control the switching of the NFET driver 38 such that the NFET driver 38 pulls the output pin OUT 44 towards the ground supply GND. By appropriately controlling the switching of the PFET and the NFET drivers using the controller 24, the output voltage at OUT 44 may be controlled. Exemplary internal structures of the FET drivers and/or the high end and low end drivers are well known to those skilled in the art, and hence, a more detailed discussion is omitted herein. The controller 24 may receive feedback voltage Vout 78 through the feedback pin FB 52, and regulate the switching of the PFET and the NFET drivers such that Vout is substantially equal to the reference voltage Vref. In various embodiments, Vout may be proportional to the reference voltage Vref, i.e., Vout may be substantially equal to N*Vref, where N is a programmable constant.
In various embodiments, the on-chip regulator 10 may act as a down convertor, by generating output voltage (e.g., 1.2V or 2.5V) less than or equal to the supply voltage VDD (e.g., 5V). In various embodiments, the voltage regulator 10 may be utilized in a plurality of electronic systems. For example, in a hard disk drive (HDD), a motor controller may integrate one or more voltage regulators to provide regulated power supply to the motor controller and/or other components external to the motor controller (e.g., system-on-chip (SoC), preamplifiers, dynamic random access memory (DRAM) etc.).
The voltage regulator 10 may be suitable for numerous low power applications, where the power requirement of the load 76 is relatively low. But as the power requirement of the load 76 increases, the FET drivers (i.e., the PFET driver 34 and the NFET driver 38) may be needed to control relatively large current components. However, because of limited power and/or heat dissipation capabilities and/or limited current carrying capabilities of the FET drivers and/or chip 20, it may not always be possible to have on-chip FET drivers for high power applications. In these types of applications, in various embodiments, it may be possible to have external FET drivers, while other components of the regulator and the controller may still be inside an integrated circuit chip.
FIG. 2 illustrates another exemplary on-chip voltage regulator 100, included in an integrated circuit chip 120 and configured to be coupled to one or more external FET drivers. Similar to the voltage regulator 10 of FIG. 1, the voltage regulator 100 of FIG. 2 may be configured to supply regulated voltage to load 176, inductor 172 and/or capacitor 174, and may include a driver 128. The driver 128 may include a high side driver 132 and a low side driver 136.
However, unlike the voltage regulator 10 of FIG. 1, the voltage regulator 100 of FIG. 2 may not include any internal FET drivers (i.e., PFET drivers and/or NFET drivers). Instead, the voltage regulator 100 may be coupled to external FET drivers (high side PFET 134E and low side NFET 138E) that may be external to the voltage regulator and/or external to the chip 120. Thus, in various embodiments, the external FET drivers may be a part of the load 176, be a part of one or more external components (that is external to the chip 120), and/or may be stand alone FET drivers external to the chip 120. The high side driver 132 may control the switching of the external high side PFET 134E through a high gate pin HG 154, and the low side driver 136 may control the switching of the external low side NFET 138E through a low gate pin LG 156.
In various embodiments, the operation of the voltage regulator 100 may be similar to the voltage regulator 10 of FIG. 1. For example, the high side driver 132 may control the switching of the external PFET driver 134E (through pin HG 154) such that the PFET driver 34 drives the output pin OUT 144 towards the supply voltage 140. On the other hand, the low side driver 136 may control the switching of the external NFET driver 138E such that the NFET driver 138E pulls the output pin OUT 144 towards the ground supply GND. By appropriately controlling the switching of the external FET drivers using controller 124, the output voltage at OUT 144 may be controlled. The controller 124 may also receive feedback voltage Vout 178 through the feedback pin FB 152, and regulate the switching of the external PFET and the NFET drivers such that Vout is substantially equal to the reference voltage Vref.
The external FET drivers of FIG. 2 may have more power and/or heat dissipation capabilities and/or more current carrying capabilities as compared to the internal FET drivers of FIG. 1. Accordingly, in various embodiments, the voltage regulator 100 of FIG. 2 may be used for applications where there is a relatively higher power/load requirement. For example, the voltage regulator 100 may be used in high performance 2.5″ mobile HDD, desktop 3.5″ drives, enterprise drives, etc. In these applications, the regulator control may be integrated within a chip, whereas the FET drivers may be external to the chip.
Thus, FIG. 1 illustrates an on-chip voltage regulator 10 with internal FET drivers, whereas FIG. 2 illustrates another on-chip voltage regulator 100 where the FET drivers are not part of the chip. As previously discussed, the voltage regulator 10 may be suitable for relatively low power applications, whereas the voltage regulator 100 may be suitable for high power applications.
However, an IC chip may be used for a number of applications, with varying requirements of regulatory output capabilities. Moreover, the chip 20 of FIG. 1 (including the regulator 10) may not be used with external FET drivers. Similarly, the chip 120 of FIG. 2 (including the regulator 100) may not be used with external components that lack external FET drivers. Thus, it may be necessary to maintain two sets of IC chips: one with internal FET drivers (like FIG. 1) and the other without internal FET drivers (like FIG. 2), and only one of the two sets of chips may be used for a particular application, based on a configuration of external components (e.g., based on a presence or an absence of external FET drivers in the external components), in addition to being based on the power requirement of the load and/or the external components.